How can you measure 9liter using 2 gallons of 12 liters and 5 liters?
8 Steps
Steps <------> 2L Gallon <-------> 5L Gallon
1<--------------->12<--------------->0
2<--------------->07<--------------->5
3<--------------->07<--------------->0
4<--------------->02<--------------->5
5<--------------->02<--------------->0
6<--------------->00<--------------->2
7<--------------->12<--------------->2
8<--------------->09<--------------->5
I had an infinite supply of water and a 5 liters and 3 liters jars.
How would you measure exactly 4 liters in least number of steps ?
1. Fill 5 litre jar ( 5j - 5, 3j - 0)
2. Transfer to 3 litre jar (5j - 2, 3j - 3)
3. Empty 3 litre jar ( 5j - 2, 3j - 0)
4. Transfer 2 litre from 5 litre jar to 3 litre jar (5j - 0, 3j - 2)
5. Fill 5 litre jar(5j - 5, 3j - 2)
6. Transfer 1 litre from 5 litre jar to 3 litre jars(5j - 4, 3j - 3)
You have 21 jars with you. Out of them, 7 are filled with water, 7 are half-full with water and 7 are empty. How will you distribute the jars among three people such that each one of them gets the equal number of jars and equal amount of water?
Give 3 full, 1 half-full and 3 empty bottles to the first person.
Give 3 full, 1 half-full and 3 empty bottles to the second person.
Give 1 full, 5 half-full and 1 empty bottle to the third person.
How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?
Let the hourglass with 7 minutes timeframe be x and the hourglass with 11 minutes timeframe be y.
Turn x and y together.
After seven minutes, turn x.
After 11 minutes, turn x again.
Now it will take 4 minutes for x to stop.
At that moment, you would have calculated 15 minutes.
There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?
Burn one candle from both the ends and simultaneously burn the other candle from just one end. In half an hour, the first candle would have been burnt fully and the second one would have been burnt half. Now light the other end of the second candle as well. In this way, the second candle will take only half the time (30/2 = 15) to burn fully.
Thus, you will have measured forty five minutes.
You have a 12 liters jug full of water. You have two empty 8 liters and 5 liters jug. Now can you divide the water into two equal parts using these jugs?
12l 8l 5l
12 0 0
4 8 0
0 8 4
8 0 4
8 4 0
3 4 5
3 8 1
11 0 1
11 1 0
6 1 5
6 6 0
You enter a logical virtual tournament. The first problem that is in front of you is as follows:
You have a three liters and a 5 liters measuring jars. There is a huge tank of water behind you comprising of about 100 liters of water. You have to use only these two jars and take out exactly 4 liters of water. How will you do it ?
Let us name the 5 liters and 3 liters jars as A and B respectively.
First fill A completely.
Now fill B with it completely. Now B has 3 liters of water. Pour it out completely. Now fill the remaining 2 liters of water from A to B. Now B has 2 liters of water while A is empty.
Next, Fill A again fully. Now, fill B with it (which had just 1 liters of capacity remaining). Thus now, A has exactly 4 liters of water.
Suppose you are sitting in an interview and the interviewee asks you an aptitude question.
You have three buckets with capacity 4 liters, 8 liters and 10 liters and you have a large tank of water. Now you have to measure 3 liters of water precisely using those buckets. How will you do it?
It is impossible. The reason is that we are asked to measure 3 liters which is an odd number but the buckets we have can contain even liters of water only (4, 8 and 10). If you hoped to fill any of the bucket half, you will not be precise in measurement.
Its a test that will check your IQ.
Suppose you have one 11 minute hourglass and one 13 minute hourglass.
Can you measure exactly fifteen minutes using them ?
First Step: Invert both the hourglasses.
Second step: When the 11 min hourglass is finished, invert it.
Third Step: When the 13 min hourglass is finished, flip the 11 min hourglass would have lost only 2 minutes till now. On inverting, we get to measure those two minutes.
Now 13 + 2 = 15 minutes.
In this way, fifteen minutes can be measured in just 3 steps.
I possess two wires. Both of them have an inconstant thickness but both of them burns completely in sixty minutes. The problem is that I want to measure forty-five minutes while using these two wires.
How can I measure if cutting the wire in half is not possible due to non-homogeneous construction ?
45minutes
It is not as hard as it seems. I will burn one wire on both ends and the other wire at one end only. The first wire will burn completely in thirty minutes and at that very moment, I will burn the other end of the second wire and it will burn in fifteen minutes. Thus both of the wires will be burnt in 30 + 15 = 45 minutes.